There is precedent for police to imagine that All currency is related to illegal activity, presumably under the shaky grounds of "otherwise you'd use a bank" [0]

But if the blockchain clearly has some dark blotches on it, then in the eyes of the police ( perhaps not completely the law ) it confirms that the pot is tainted. So, I would say in this legal environment, it would be very difficult to have both trust in the mechanics of a digital currency and also status beyond reproach of "involved in... unlawful activity"

[0] https://www.msn.com/en-us/news/us/flying-with-cash-law-enfor...